气相色谱法测定三环氧丙基异氰尿酸酯中环氧氯丙烷残留量

A simple,rapid and reliable method for the determination of trace epichlorohydrin residue in tris (2 ,3-epoxy propyl) isocyanurate for industrial use by gas chromatography is described. The gas chromatographic separation was achieved on a glass colunin packed with 4% SE-30/Chromosorb W HP at a column temperature of 80℃.The detector was FID and the carrier gas was N2.Three preducts from various manufacturers were analyzed by this methed with the coefficient of variation of 2. 2%-5. 2%。     

酯化衍生气相色谱新法测定苯甲酸与山梨酸

In this paper, it is described that tetramethyl ammonium saIts of sorbic,benzoic and phenylacetic acids reactwith 1-iedobutane directly in N,N-dimethylformamide solution to forrn butyl esters of the corresponding acids. The butyl esters can be well separated by gas chron1atography on a column packed with 5%SE-30/102 silanizedwhite support.This methed has been used for the determination of benzoic and sorbic acids in ffors and drinks。The analysis is simple,fast and accurate.     

序贯单纯形法确定高效液相色谱流动相各组分的最佳配比

Work of searching mobile phase composition in high performance liquid chromatography is usually time-consuming.This paper reports the optimization of mobile phase composition to analyse the prduct mixture in preparation of o-nitro-α- phenylcinnamic acid.The methed is simple and rapid.     

Studies on Manganese Peroxidase Immobilized in Gelatin-containing Microemulsion-based Gels

The immobilized technique of manganese peroxidase (MnP) in gelatin-containing microemulsion-based gels and the effects of storage time and reuse times on its catalytic activity were studied. The results show that the MnP immobilized together with Mn^2 and H2O2 could effectively oxidize syringaldazine in n-heptane. The immobilized MnP still had a high catalytic activity after one-month storage under a freezing condition. The reuse times have a relation to the amount of the immobilized H2O2. When the amount of the immobilized H2O2 is sufficient, the microemulsion-based gels containing MnP could be used many times.     

高效液相色谱法测定六亚甲基二乙酰胺注射液含量

Hexamethylene Bizacetamide content was determined by high performance liquid chromatography using ananalytical column(15 × 0. 46cm i.d. )packed DU PONT ZORBAX-ODS(5μm)and a UV detector at 220nm andMeOH-H_2O(50 : 50 ) as eluent.The quantitative determination was performed with caffeine as the internalstandard.The methed is satisfactory for the quality control of hexamethylene bizacetamide.     

Scanning electrochemical microscopy-development of instrumentation utilizing piezo-bimorph X-Y scanners

The development of the instrumentation of a scanning electrochemical microscopy (SECM) is presented. The core of the SECM sensing system is constructed based on piezobimorph scanners, a mechanical micropositioner of multi-dimensional adjustment and ultramicroelectrodes. The control of the electrochemical cell and the SECM system is realized by a battery powered bipoteniostat and analog control circuits respectively with the control of a microcomputer work station. The demonstrations of SECM experiments are given on both a standard IDA sample and a silver electrode. Discussions on the resolution and quality of SECM image are made.     

Catalytic activity of phosphorus and steam modified HZSM-5 and the theoretical selection of phosphorus grafting model

The modification of HZSM-5 zeolite with phosphorus and steam has been studied. Results show that 1% phosphorus and steam modified HZSM-5 has the highest catalytic activity for n-heptane. Physicochemical and catalytic properties of 1% phosphorus and steam modified HZSM-5 zeolites have been investigated. The X-ray diffraction （XRD） results exhibit that there is considerable variation in the relative intensity of the individual diffraction peaks. The acidity of the samples decreases with an increase in the steaming temperature, which is determined by the IR of adsorbed pyridine and temperature programmed desorption （TPD） of ammonia. The oxidation state of phosphorus shown by XPS is ＋5, and a model for surface structure modification is proposed. The nitrogen adsorption isotherm for all samples is a combination of type I and type IV, all hysteresis loops resemble the H4-type. The density functional and cluster model methods have been invoked to select the phosphorus grafting model, and it was found that the phosphorus grafting model were more probable in the form of the terminal oxygen coordinating with aluminum.     

离子色谱法（安培检测器）测定血清、尿及头发中微量碘

This paper intreduces a reasonable pretreatment method for IC-amperometric method employed to measuretrace amount of iodine in serum, urine and hair. The resultant graph is simple and clear,and withoutinterference in a general way. The limits of detection for iodine in serum,urine and hair are 0.007,0.003μg/mL and 0. 046μg/g, respectively.The recovery of iodine added into the sample is 82～93%. The coefficient ofvariation is less than 9%. Trace amount of bromine in the sample can also be measured simultan     

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION*

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of anew concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined asthe molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertiblewith the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume ofthe polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts forthe non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamicvolume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpretedby the concept of self-association. The concept of self-association allows us to predict the existence of a boundaryconcentration C_s (dynamic contact concentration) which divides the dilute polymer solution into two regions.     

ADSORPTION OF 1,2,4-ACID BY WEAKLY BASIC RESIN： ISOTHERMS, THERMODYNAMICS AND KINETICS

The adsorption properties, including the adsorption isotherms, thermodynamics and kinetics, of l-amino-2-naphthol-4-sulfonic acid (1,2,4-acid) onto weakly basic resin ND900 are investigated. Both the Langmuir and Freundlich equations can give a good fit to the adsorption isotherms, which indicates an endothermic and a favorable adsorption in our study range. A high yield in elimination of about 45.21%-97.28% is obtained for the tested adsorption systems. The capacity and affinity of the adsorption increase with temperature, due to the phenomena of “solvent-motivated” effects. The value of ΔH is 51.59 kJ/mol, which indicates a chemical adsorption and then expects the poor desorption property of ND900. The negative value of ΔG indicates the spontaneous nature of the adsorption process, and the positive value of ΔS shows the increased randomness at the solid/solution interface during the adsorption process. The value of the adsorption rate constant lower than 0.013 min^-1 is indicative of a slow adsorption rate. The intra-particle diffusion must be one of the rate limiting steps.     

基于自组织特征映射神经网络的金银花分类研究

自组织特征映射神经网络(SOM)以无监督方式进行网络训练,具有自组织功能。网络通过自身训练,自动对输入模式进行分类。中药药用价值与其所含微量元素有直接的关系,药材分类是中药质量控制的重要方法。将金银花中微量元素含量作为网络输入,利用自组织特征映射神经网络对不同产地金银花进行分类。结果表明分类效果较好,符合生产实际。     

高效液相色谱法同时测定款冬花中四种酚酸

建立了同时测定款冬花中没食子酸、绿原酸、咖啡酸和阿魏酸的高效液相色谱方法。采用Sepax Gp-C18色谱柱(250×4.6mm,5μm),以甲醇-0.5%乙酸溶液为流动相梯度洗脱,流速1.0mL/min,柱温30℃,检测波长280nm,20min内4种酚酸可实现基线分离。结果表明,各组分在一定浓度范围内呈良好线性关系,相关系数均大于0.9990,检测限为0.05~0.14mg/L,平均回收率在92.3%~102.0%之间,相对标准偏差为0.27%~2.70%,且不同来源的款冬花中4种酚酸的含量有明显差异。该方法简便、快速、准确、重复性好,可作为款冬花药材质量控制的方法。     

金银花中绿原酸的微波预处理提取及检测

采用微波预处理法对金银花中绿原酸的提取进行优化,用三波长法测定了绿原酸的含量.设计正交试验,以绿原酸的含量为指标,考察乙醇用量、乙醇浓度和微波处理时间对金银花中绿原酸提取工艺的影响.三波长法检测波长为λ1=280 nm,λ2=325 nm,λ3=380 nm,其回归方程为ΔA=0.0426C 0.0017,相关系数为R=0.998.结果表明在气化剂用量20 mL,乙醇浓度为70(,微波辐射70 s时绿原酸得率最高.与常用的提取和测定方法相比,此方法对设备要求不高,具有更高的准确性与精密度.     

HPTLC-densitometric method of determination of oleanolic acid in the Lamii albi flos

HPTLC combined with densitometric method was used to determine the content of oleanolic acid in acetone extract from the Lamii albi flos L. The plant extract was separated on Si 60 HPTLC plates and determined with the use of two densitometric methods: measurement of fluorescence and absorbance. The content of oleanolic acid was statistically calculated. In a measurement of absorbance in 1 g of the dry Lamii albi flos L. 1458 microg of oleanolic acid was determined (0.147%). In a fluorescence method in 1 g of the plant material 1516 microg of oleanolic acid was determined (0.149%).     

中药血清药理学研究金银花的抑菌活性

采用最低抑菌浓度(MIC)测定方法和抑菌活性试验,考察不同产地的金银花以及含药血清的抑菌效果。试验结果为:含药血清对大肠杆菌和金黄色葡萄球菌的MIC分别为0.5μg绿原酸/mL和0.25μg绿原酸/mL;含药血清抑菌活性为高敏。     

Integrating Anti-Influenza Virus Activity and Chemical Pattern Recognition to Explore the Quality Evaluation Method of Lonicerae Japonicae Flos

Lonicerae japonicae flos (LJF, Lonicera japonica Thunb.) is adopted as a core herb for preventing and treating influenza. However, the anti-influenza virus components of LJF and the impact of quality-affecting factors on the anti-influenza activity of LJF have not been systematically investigated. In this study, a strategy integrating anti-influenza virus activity, ultrahigh-performance liquid chromatography fingerprint and chemical pattern recognition was proposed for the efficacy and quality evaluation of LJF. As a result, six bioactive compounds were screened out and identified as neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, 4,5-Di-O-caffeoylquinic acid, sweroside and secoxyloganin. Based on the bioactive compounds, chemical pattern recognition models of LJF were established by a linear discriminant analysis (LDA). The results of the LDA models and anti-influenza virus activity demonstrated that cultivation pattern significantly affected the anti-influenza effect of LJF and that the neuraminidase inhibition rate of wild LJF was significantly higher than that of cultivated LJF. Moreover, the quality of LJF samples with different processing methods and geographical origins showed no obvious difference. Overall, the proposed strategy in the current study revealed the anti-influenza virus components of LJF and provided a feasible method for thequality evaluation of LJF, which has great importance for assuring the clinical effect against influenza of LJF.     

Characterisation of Some Phytochemicals Extracted from Black Elder (Sambucus nigra L.) Flowers Subjected to Ozone Treatment

Elderflowers are a well-known source of bioactive compounds. The amount of isolated bioactive compounds may be increased by applying various abiotic and biotic factors. Gaseous ozone (10 and 100 ppm) was used in the process of preparing flowers. Next, the flowers were treated with sugar syrup to extract bioactive compounds. It was shown that this treatment, including the influence of extraction temperature, significantly affects the contents of polyphenols (liquid chromatography–mass spectrometry (LC–MS) methods) and vitamin C, as well as the antioxidant potential (cupric reducing antioxidant capacity (CUPRAC method)), the profile of volatile substances (head space–solid-phase microextraction (HS–SPME methods)) and the colour of the syrup (Commission Internationale de l’Eclairage (CIE) L*a*b* methods). The findings show that an increased dose of ozone and higher extraction temperature applied in the process of syrup production resulted in higher contents and different compositions of bioactive compounds. The highest contents of bioactive compounds were identified in syrup obtained from raw material treated with ozone for 15 min (concentration = 10 ppm) and extraction with sugar syrup at a temperature of 60 °C.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.